Electric motor



Oct. 12, 1937. J, OWENS 2,095,281

ELECTRIC IIO'I'OR Filed lay 6, 1936 INVENTOR JAMES OWENS ATTORNEY motors must be supplied Patented on, 12, 1937 2,095,281

'UNITED'STATES PATENT OFFICE ELECTRIC MOTOR James H. Owens, Idlewylde, M1, asaignor to Badio Corporation of America, a corporation of Delaware Application May 6, 1936, Serial No. 78,0 86 4 Claims. (Cl. 172-278) This invention relates to electric motors, and more than one speed, which method will be inmore particularly to induction motors of the caexpensive and simple to carry out.

Pacitor type. In accordance with my invention, I insert, in It is wellknown that an induction motor which is provided with an auxiliary, or starting, winding, a potentiometer, 5 or variable resistor, across said auxiliary winding and by adjustment oi the potentiometer, the

the current through the main, or running, windtorque, and in this manner, the speed of the mo- 10 ing of the motor. It is also well known that motor and of the parts driven thereby may be adjusted. Y

The novel features that I consider characteristic of my invention are cases it is desirable to operate a phonograph turntable at the standard speed 01' 78 R. P. M., for example, while in other cases it' is desirable to operate the turntable at a reduced a moving picture machine.

Referring more specifically The primary object of my invention is to provide an improved motor of the type set forth which will not be subject to the foregoing and other disadvantages of similar motors of the prior art.

More specifically, it is tion to provide an improved induction motor the motor. For controlling the speed of the motor, I pro- 45 vide a variable resistor starting closed, a portion of the current which would normally flow through the inductance or winding 3 is diverted through the resistor iii. The effect of the resistor I5 is, therefore, to change the effective inductance and reactance of the winding 3, and, since it places a load on the capacitor I, it also changes the efiective capacitance and reactance of the capacitor, the result being that the tuning of the series connected inductance 3 and capacitance I is changed. In other words, the

phase displacement between the current in the running winding or inductance 5 and that in the starting winding 3 is changed, and therefore the motor will rotate at a slower speed depending upon the adjustment of the potentiometer 85. In some cases, the motor may not start with the switch 11 in closed position. Hence, to start the motor, the switch i1 is opened and the switch I3 is closed. After the motor has begun to rotate, the switch I1 is also closed either manually,

or it will be closed automatically when a predetermined speed has been reached, if controlled bya centrifugally operated device.

Although I haveshown but a single form of my invention, it will be obvious to those skilled in the art that many modifications thereof are possible. I desire, therefore, that my invention shall not be limited except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim as my invention:

1. In an electric motor, a running winding, a winding connected in parallel with said running winding, a capacitor in series with said starting winding for prod cing a phase displacement between the current in each of said windings, and a variable resistor associated with said starting winding and said capacitor for changing the efiective reactance of said starting winding circuit whereby to control the speed of the motor.

2. In an electric motor, a pair of inductive windings connected in out of phase relationship with each other, a current controlling capacitor in series with one of said windings, and a variable resistor connected in shunt relation to said last named winding for varying said phase relationship.

3. In an electric motor, a pair of inductive windings connected in out with each other, a current controlling capacitor in series with one of said windings, a variable resistor arranged to be connected in shunt relation to said last named winding whereby to vary said phase relationship, and means for coupling and uncoupling said resistor and said last named winding.

4. In an electric motor, a pair of inductive windings connected in out of phase relationship, one of said windings being adapted to act as a starting winding, a current controlling capacitor in series with said starting winding, a manually operable variable resistor connected in shunt relation to said starting winding for varying said phase relationship whereby to vary the speed of the motor, and means in circuit with said resistor for rendering it ineffective during starting of the motor.

JAMES H. OWENS.

of phase relationship 

